Hello all. I am fairly new to the world of Mac's and not all that great with any computer really. I have a 2010 model Macbook Pro that I recently tried to update from Lion to Mountain Lion. My friend gave me a disk to do the update with. Well when I started to do the update all seemed well and good. But it never actually updated. It just kept getting to a certain point and starting all over again. Now I am locked up and all I get when I start the Mac up is a message screen to install or update the OS. I tried disc utilities and was willing to just start all over and erase and repartition. But that says can not unmount drive. I tried time machine there is no backup in there. I have also tried to go back to snow leopard disc and just start from scratch installing that OS. But same thing, it just gets to a point and starts over. I am having no luck with it at all. It will not do a complete install of any OS as far as I can tell. I need some help. Maybe I am just missing something really simple here. But please understand that I do not know a lot of the terms and what not and will need good details on any ideas anyone has to help me get it back up and running. Thank you for reading my thread.